Viskoelastik Malzemeli Kemik-plak Sisteminin Performans Açısından Değerlendirilmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2008Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2008Bu çalışmada, prototipi üretilmiş viskoelastik malzemeli kemik plağı, sonlu elemanlar yöntemi kullanılarak performansı açısından değerlendirilmiştir. Bu amaçla, viskoelastik malzemeli, Ti alaşımlı ve paslanmaz çelikten (316L) imal edilmiş kemik plaklarının uzun tibia kemiğine vidalarla bağlanmış üç boyutlu sonlu elemanlar modeli ANSYS programı kullanılarak oluşturulmuş ve aynı yükleme ve sınır koşulları altında gerilme analizleri yapılmıştır. İyileşmenin olmadığı durum için plakların orta kesitlerinde meydana gelen maksimum çekme ve basma gerilmeleri teorik olarak hesaplanmıştır. Elde edilen sonuçların nümerik sonuçlarla uyuştuğu görülmüştür. Kemiğin iyileşmesi sürecinde kırık ara yüzeyinde meydana gelen gerilmeler üç farklı kemik-plak sistemi içinde incelenmiş, elde edilen sonuçlar grafiksel olarak gösterilerek karşılaştırılmıştır. Viskoelastik malzemeli kemik plağının, paslanmaz çelik ve Ti alaşımlı kemik plağına kıyasla kırık ara bölgesinde gerilme kalkanını azaltarak iyileşmeyi hızlandıracak daha büyük basma gerilmeleri meydana getirdiği tespit edilmiştir.In this study, the bone plate with viscoelastic material, prototype of which was made, was evaluated in terms of its performance. For this reason, 3D finite element models of the bone plate with viscoelastic material and traditional bone plates, made of stainless steel (316L) and Ti alloy, have been developed by using ANSYS program and their stress analyses have been carried out under the same loading and boundary conditions. Maximum compressive and tensile stresses occurring in the middle sections of the bone plates in the beginning (there is no callus formation) have been calculated theoretically. These values have been compared with analysis results so that it could be verified that the results of numerical study were reasonable. Compressive stresses occurring in the intact portion of the bone (tibia) and at the fractured interface at the different stage of bone-healing have been investigated for all the three types of fixation. The results obtained have been compared and shown in graphs. It has been determined that the bone plate with viscoelastic material offers less stress-shielding to the bone, providing higher compressive stress at the fractured interface to induce accelerated healing in comparison with Ti alloy and stainless steel bone plate

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Antiagregan ve Antikoagülan Tedavi Alan Hastalarda Endoskopik Retrograd Kolanjiyopankreatografi İşlemi Sonrası Kanama Komplikasyonlarının Değerlendirilmesi

Endoscopic Retrograde Cholangiopancreatography (ERCP) procedure has become an important interventional procedure for biliary and pancreatic duct diseases. In addition to its important therapeutic indications, a variety of procedure-related adverse events have been reported, which have decreased over the years thanks to advances in science, technical equipment and experience. Bleeding complications related to endoscopic sphincterotomy (ES) performed with ERCP procedure are gaining importance due to the widespread use of antiaggregant and anticoagulant drugs. To optimize the risk of bleeding associated with these drugs, several guidelines have made recommendations regarding the management of drugs before and after the procedure. In this study, 666 adult patients who underwent ERCP procedure and underwent endoscopic sphincterotomy in Hacettepe University Faculty of Medicine Endoscopy Unit between May 2018 and December 2021 were included, and it was aimed to determine the risk factors that may be associated with bleeding, as well as the relationship between the use of antiaggregant and anticoagulant drugs and bleeding complications. Of the 666 patients included in the study, 365 (54.8%) were female and the median age was 58.5 years. In addition, 76 (11.4%) of the patients were using at least one antiaggregant or anticoagulant drug. Bleeding complications were detected in 17 (2.6%) patients. While 58% (n=10) of these hemorrhages were observed during the procedure, 42% (n=7) presented as late bleeding. The majority of patients with clinical bleeding were mild (70%, n=12). No bleeding-related mortality was detected. A statistically significant correlation was found between prophylactic NSAID administration (OR: 3.89, CI: 1.36-11.13, p=0.011), antiaggregant drug use (OR: 6.43, CI: 1.52-27.05, p=0.011), anticoagulant drug use (OR: 7.12, CI: 1.9-26.7, p=0.004), sepsis (OR: 19.2, CI: 2.98-123.7, p=0.002), creatinine levels (0.73 vs. 0.88, IQR 0.30 vs. 0.25, p=0.016) and bleeding complications. Even if the guidelines for the correct use of antiaggregant and anticoagulant drugs with endoscopic procedures were followed, there was an independent factor increasing the risk of bleeding. Patients using these drugs should be followed carefully in terms of bleeding.Endoskopik Retrograd Kolanjiopankreatografi (ERKP) işlemi biliyer ve pankreatik kanal hastalıkları için önemli bir girişimsel işlem halini almıştır. Önemli terapötik endikasyonlarının yanında işlem ile ilgili çeşitli advers olaylar bildirilmiş, bu advers olaylar geçen yıllar boyunca bilim, teknik ekipmanlar ve deneyimdeki ilerlemeler sayesinde azalmıştır. ERKP işlemi ile uygulanan endoskopik sfinkterotomi (ES)’ye bağlı kanama komplikasyonları, antiagregan ve antikoagülan ilaç kullanımının da yaygınlaşması nedeniyle giderek önem kazanmaktadır. Bu ilaçlara bağlı kanama riskini optimize etmek için çeşitli kılavuzlar işlem öncesi ve sonrası ilaçların yönetimi ile ilgili önerilerde bulunmuştur. Bu çalışmada Mayıs 2018-Aralık 2021 arasında Hacettepe Üniversitesi Tıp Fakültesi Endoskopi Ünitesi’nde ERKP işlemine alınarak ES uygulanan 666 yetişkin hasta dahil edilmiş ve hastaların kanama ile ilişkili olabilecek risk faktörlerinin yanında antiagregan ve antikoagülan ilaç kullanımı ile kanama komplikasyonu arasındaki ilişkinin belirlenmesi amaçlanmıştır. Çalışmaya alınan 666 hastanın 365’i kadın (%54.8) ve ortanca yaş 58.5 idi. Hastaların 76’sı (%11.4) en az bir antiagregan ya da antikoagülan ilaç kullanıyordu. Hastaların 17’sinde (%2.6) kanama komplikasyonu saptandı. Bu kanamaların %58’i (n=10) işlem sırasında görülürken, %42’si ise (n=7) geç kanama şeklinde kendini gösterdi. Klinik olarak kanama saptanan hastaların büyük çoğunluğu hafif kanama şeklindeydi (%70, n=12). Kanama ile ilgili mortalite saptanmadı. Profilaktik NSAİİ verilmesi (OR: 3.89, CI: 1.36-11.13, p=0.011), antiagregan ilaç kullanımı (OR: 6.43, CI: 1.52-27.05, p=0.011), antikoagülan ilaç kullanımı (OR: 7.12, CI: 1.9-26.7, p=0.004), sepsis (OR: 19.2, CI: 2.98-123.7, p=0.002) ve kreatinin düzeyi (0.73 vs. 0.88, IQR 0.30 vs. 0.25, p=0.016) ile kanama komplikasyonları arasında istatiksel olarak anlamlı bir ilişki saptandı. Antiagregan ve antikoagülan ilaçların, endoskopik işlemler ile doğru kullanımına ilişkin kılavuz önerilerine uyulsa bile, kanama riskini artıran bağımsız bir faktör olduğu görüldü. Bu ilaçları kullanan hastaların kanama açısından dikkatli takip edilmesi gereklidir

Evaluation of bone plate with low-stiffness material in terms of stress distribution

WOS: 000261657000020PubMed ID: 18805533The aim of this study is to evaluate a newly developed bone plate with low-stiffness material in terms of stress distribution. In this numerical study, 3D finite element models of the bone plate with low-stiffness material and traditional bone plates made of stainless steel and Ti alloy have been developed by using the ANSYS software. Stress analyses have been carried out for all three models under the same loading and boundary conditions. Compressive stresses occurring in the intact portion of the bone (tibia) and at the fractured interface at different stages of bone healing have been investigated for all three types of bone-plate systems. The results obtained have been compared and presented in graphs. It has been seen that the bone plate with low-stiffness material offers less stress-shielding to the bone, providing a higher compressive stress at the fractured interface to induce accelerated healing in comparison with Ti alloy and stainless-steel bone plate. In addition, the effects of low-stiffness materials with different Young's modulus on stress distribution at the fractured interface have been investigated in the newly developed bone-plate system. The results showed that when a certain value of Young's modulus of low-stiffness material is exceeded, increase in stiffness of the bone plate does not occur to a large extent and stress distributions and micro-motions at the fractured interface do not change considerably. (C) 2008 Elsevier Ltd. All rights reserved

Is Ki67 Effective as a Prognostic Marker in Node-Positive Breast Cancer Patients?

Ki67 is a proliferation marker commonly assessed by immunohistochemistry in breast cancer, and it has been proposed as a clinical marker for subtype classification, prognosis, and prediction of treatment modalities. Therefore, this study aimed to evaluate the prognostic significance of Ki67 in node-positive breast cancer. A total of 251 cases of axillary lymph node-positive breast cancer were included in the study. Several clinicopathologic factors were collected: age, menopausal status, tumor size, node involvement, tumor grade, estrogen and progesterone receptors, HER2, and Ki67 expression. We analyzed if these parameters could be considered as a prognostic factor. Associations of the Ki67 index with other prognostic factors were evaluated both as continuous and categorical variables. Breast cancer-specific survival analysis of the ki67 level was evaluated with Kaplan–Meier survival curve and Cox regression model adjusted for a known prognostic factor. The majority of patients was alive and without tumor relapse at the moment of the analysis (90.8%). A cutoff of 20% separated tumors into a Ki67-low (n = 94) or Ki67-high group (n = 157). The breast cancer-specific survival was 92. 6% and 89.8% for Ki67-low and Ki67-high groups, respectively. Univariate and multivariate analysis showed that in this lymph node-positive clinical trial, the predictors for breast cancer survival were higher N stage and triple-negative subtype was independent predictors of breast cancer death. Although the Ki67 index is an effective complementary proliferative tool in breast cancers without lymph node involvement in predicting prognosis and survival, our study shows that it is not an effective tool for showing prognosis and survival in node-positive breast cancer patients